A hernia is the protrusion of an organ or the fascia of an organ through the abdominal wall. This occurs when the abdominal walls weaken either from incorrect formation at birth, recent surgery or trauma. The most common types of hernias are inguinal and incisional. Inguinal hernias occur in the groin area in both males and females but they are most common in men to the right and left of the midline where the spermatic cords and arteries pass through the spaces in the abdominal wall. There are three possible spaces in the abdominal wall for the hernia to pass through: direct, indirect and femoral. The direct space is medial to the epigastric vessels while the indirect space is lateral to the epigastric vessels. A femoral hernia occurs when the organs protrude through a large femoral ring into the femoral canal. Incisional hernias occur after a surgery when the abdominal wall does not heal correctly, causing the internal organs and fascia to push through.
Hernias can be repaired by either open or laparoscopic surgery. In laparoscopic surgery, a trocar is inserted to access a body cavity and to create a channel for the insertion of a camera, such as a laparoscope. The camera provides a live video feed capturing images that are then displayed to the surgeon on one or more monitors. Another trocar is inserted to create a pathway through which surgical instruments can be passed for performing procedures observed on the monitor. The targeted tissue location such as the abdomen is typically enlarged by delivering carbon dioxide gas to insufflate the body cavity and create a working space large enough to accommodate the scope and instruments used by the surgeon. The insufflation pressure in the tissue cavity is maintained by using specialized trocars. Laparoscopic repair has many advantages over the traditional open surgery repair including quicker recovery and less pain. Therefore, it is often more desirable for the patient to undergo a laparoscopic repair. However, laparoscopic repair requires an experienced surgeon. In order for surgeons to practice laparoscopic hernia repairs, a realistic, anatomically correct model for use in a laparoscopic training device is needed.
Generally, there are two ways to repair an inguinal hernia laparoscopically. The first and more often taught way is called transabdominal pre-peritoneal (TAPP). The TAPP approach involves placing the laparoscopic instruments all the way into the insufflated abdominal cavity and approaching the hernia from below by cutting a hole in the peritoneum. The hernia is then resected, mesh is placed over the weakened abdominal wall and the peritoneum is closed. The second way of reducing an inguinal hernia is called total extraperitoneal (TEP). The TEP approach is more difficult since it involves entering the space between the peritoneum and the abdominal wall without puncturing the peritoneum. Once the trocar has been inserted into that space, a balloon is used to open up the space to allow for easier movement of the instruments and less blunt dissection. When the balloon is removed, the space is insufflated and the hernia is found in that same plane. When the hernia is found, it is resected back into the abdominal cavity, the peritoneum laid flat and mesh placed over the weakened abdominal wall. When surgeons are learning how to perform laparoscopic surgery, they are taught TAPP first since like most other laparoscopic procedures, it is performed inside the abdominal cavity. TEP is considered more advanced and surgeons need a way to safely learn and practice the procedure. Due to the need for a safe practice model for both beginner surgeons learning TAPP as well as more advanced surgeons learning TEP, a hernia model that allows for both procedures to be practiced is needed.
In order to help patient outcomes and recoveries, surgeons need a way to practice laparoscopic hernia repairs outside of the operating room. The practice model needs to be anatomically correct and include all important landmarks normally seen during surgery in order to give the surgeon or resident the most realistic practice possible. Additionally, the model should allow the surgeon to practice incisional and inguinal (TAPP and TEP) procedures.